Good Samaritan Left for Dead on City Sidewalk

A psychologist believes there could be several reasons why people didn't offer to help Hugo Alfredo Tale-Yax, 31 -- whose fate was captured on a grainy surveillance video -- perhaps including our culture's desensitization to violence from so much exposure in movies, video games and music.

"We love violence in this culture," said the psychologist, Michael Bradley. "We have this kind of 24/7 pounding of violence. We now know that that pounding of violence actually causes brain changes where people start to not distinguish between real violence and cyberviolence. We're actually rewiring our brains to not react to violence and pain the way we should."

Bradley said there are several explanations for why passersby may not have taken action.

For one thing, he said, people tend to copy the behavior of others, so if one person ignored the injured man, then others were likely to do the same thing.

People also think it's someone else's responsibility to intervene, so they won't do anything because they assume another person will call for help.